Method and apparatus for objective assessment of in-ear device acoustical performance

Abstract

A method and apparatus for objectively assessing acoustical performance of an in-ear device having a passageway extending there through use a dual microphone probe that removably engages the passageway. The acoustical performance of the in-ear device is performed with the in-ear device inserted into the ear canal of the user and a reference sound source. A clip holding the probe in an acoustic near field of the sound source permits real time calibration thereof. The method and apparatus allow on-site and in-situ measurement of a predicted personal attenuation rating of the device, a subject-fit re-insertion test, an acoustic seal test, a rating test, a stability and reliability test, as well as a protection test of the device with an assessment of a filtered predicted exposure level at the ear for a specific noise exposure level. The apparatus may be simply housed along with the sound source for in-field evaluation tests.

The invention claimed is: 
     
       1. An apparatus for objectively assessing in-situ an acoustic seal of an in-ear device in field environment conditions, the apparatus comprising:
 a controller unit operatively connectable to a sound source and to a sound measurement device; 
 wherein the sound measurement device may be selectively engaged in a first position relative to an in-ear device to measure a first sound level outside the ear canal; 
 wherein the sound measurement device may be selectively engaged in a second position relative to the in-ear device, such position occluding a passageway in the in-ear device, to measure a second sound level inside the ear canal; 
 a supporting device that is mountable on the sound source, releasably supporting the sound measurement device thereon. 
 
     
     
       2. The apparatus of  claim 1 , wherein the supporting device is a resilient clip mountable on the sound source, the clip releasably and resiliently holding the sound measurement device. 
     
     
       3. The apparatus of  claim 1 , wherein the controller unit controls operation of the sound source. 
     
     
       4. The apparatus of  claim 1 , wherein the controller unit includes the sound source. 
     
     
       5. The apparatus of  claim 1 , further including a user interface unit operatively connecting to the controller unit. 
     
     
       6. The apparatus of  claim 5 , wherein the controller unit analyzes the reference sound level and assesses calibration of the sound measurement device, the controller unit communicating with the user interface unit to indicate to the user proper functioning of the sound measurement device. 
     
     
       7. The apparatus of  claim 1 , wherein the sound measurement device is a first sound measurement device, the apparatus further including a second sound measurement device operatively connecting to the controller unit, the first sound measurement device being selectively engaged in a first position relative to the in-ear device for measuring the first sound level outside the ear canal, the second sound measurement device being selectively engaged in a second position relative to the in-ear device, such position occluding a passageway in the in-ear device, to measure a second sound level inside the ear canal. 
     
     
       8. The apparatus of  claim 7 , wherein the first and second sound measurement devices are connected to one another. 
     
     
       9. The apparatus of  claim 8 , wherein the first and second sound measurement devices are connected in a back-to-back relationship relative to one another. 
     
     
       10. The apparatus of  claim 8 , wherein the first and second sound measurement devices form a dual microphone probe. 
     
     
       11. The apparatus of  claim 7 , further including a user interface unit operatively connecting to the controller unit. 
     
     
       12. The apparatus of  claim 11 , wherein the controller unit analyzes the first and second sound levels and assesses calibration of the first and second sound measurement devices, said controller unit communicating with the user interface unit to indicate to the user proper functioning of the first and second sound measurement devices. 
     
     
       13. The apparatus of  claim 11 , wherein the controller unit analyzes the first and second sound levels and assesses validity of the first and second sound levels, the controller unit communicating with the user interface unit to indicate to the user proper measurements of the first and second sound levels. 
     
     
       14. The apparatus of  claim 13 , wherein the controller unit further assesses an acoustic seal of the in-ear device by comparing the first and second sound levels to one another, said controller unit communicating with the user interface unit to indicate to the user proper acoustic seal of the in-ear device inside the ear. 
     
     
       15. The apparatus of  claim 13 , wherein the controller unit further assesses an acoustic seal of the in-ear device by comparing the first and second sound levels to one another and by using a transfer function determined from the first and second reference sound levels, the controller unit communicating with the user interface unit to indicate to the user proper acoustic seal of the in-ear device inside the ear. 
     
     
       16. The apparatus of  claim 15 , wherein the controller unit further assesses an acoustic seal by further using a compensation term relating to the in-ear device. 
     
     
       17. The apparatus of  claim 5 , wherein the controller unit assesses an acoustic seal of the in-ear device by comparing the first and second sound levels to one another, the controller unit further assessing an acoustic seal by further using a compensation term relating to the in-ear device, the controller unit communicating with the user interface unit to indicate to the user proper acoustic seal of the in-ear device inside the ear. 
     
     
       18. The apparatus of  claim 5 , wherein the user interface unit includes at least one of a keypad, a keyboard, an alpha-numerical display, a speaker, a led-type display, a monitor-type display, a socket-type connection port and a wireless type connection port. 
     
     
       19. The apparatus of  claim 11 , wherein the user interface unit includes at least one of a keypad, a keyboard, an alpha-numerical display, a speaker, a led-type display, a monitor-type display, a socket-type connection port and a wireless-type connection port.